Electromagnetic disk brakes are widely used in a variety of applications such as dynamic brakes for motor input shafts and/or output shafts and as static or “holding” brakes for motors and the like. A typical electromagnetic disk brake of this type includes a friction disk that is coupled with the shaft so as to be movable axially relative to the shaft but to be rotationally fixed relative to the shaft. In static braking applications, the brake is applied by compressing the friction disk between a stationary reaction plate and an axially movable armature plate to provide the desired holding action, and the brake is released by energizing the electromagnet to retract the armature plate to allow the friction disk to rotate freely. In dynamic braking applications, the brake is applied while the shaft is rotating, either by energizing an electromagnetic actuator to overcome the force of a compression spring or by de-energizing a normally energized actuator to permit the compression spring to apply the brake.
Electromagnetic disk brakes designed specifically for use with electric motors exhibit several disadvantages. Specifically, brakes of this type require a mounting plate for attaching the brake to the motor's end shield. This mounting plate necessarily increases the size and weight of the brake, limiting the brake's usefulness in some applications. Attachment of the brake to the motor end shield often requires modification of the existing end shield structure to accept the mounting plate, which tends to be labor intensive. Furthermore, when adding a brake to motors employing an internal fan for cooling, the brake is often mounted to the fan housing. Thus, the fan is positioned between the brake and the motor, preventing cooling to the brake. The heat produced by the brake during normal operation has a deleterious effect on the stopping and starting capacity of the brake. Additionally, the heat on the brake has a deleterious effect on the life of the brake and the motor.
Conventional manual brake release mechanisms typically have significant rotational play when the brake is actuated, leading to rattling and possibly to false actuation of indicator switches which are intended to be closed only upon manual brake release. Furthermore, the manual release mechanisms typically employed in electromagnetic brakes either utilize a two step process for providing an even pull on the armature plate or a one step process which only provides a pull on one side of the armature plate.
Therefore, there is an unmet need in the art to facilitate the integration of electric motors with electromagnetic brakes for decreasing cost, size and weight of the brake, while increasing efficiency of the brake.